Dyeing of hair



Patented Jan. 11, 1944 2,338,746 prams OF HAIR Willard Frederick VanRiper, Wilmington, Del.', and Warren John Zinck, Woodstown, N. 1.,assignors to E. I. du Pont de Nemours 8; Company, Wilmington, Del

ware

., a corporation of Dela- No Drawing. Application April 3, 1942,

. Serial No. 437,594

6 Claims.

This invention relates to dyeing hair, and especially to newcompositions and new processes for such purposes. The new processes areespecially useful for the dyeing of human hair such as hair on livingpersons as well as for dyeing animal hair or fur on pelts.

Heretofore, numerous substances having ailinity for hair have beenproposed as dyes therefor, among which are the metal salts which producethe desired shades by forming oxides or sulfides. Ordinarily these metaloxides or sulfides are formed superficially and do not produce apermanent coloration. In addition some metallic compounds, such as leador silver, are toxic and users of the dyed fur or hair are subjected totoxic effects. Vegetable dyes, such as hypernic, quercitron, fustic andsumac have been used but these materials ordinarily produce weak dyeingsand there is a limited range of shades possible. Combinations of metalsalts and vegetable dyes have been used but these combinations have oneor all of the disadvantages of their several constituents. There hasbeen extended use of the so-called oxidation dyes which are amino orhydroxy derivatives of aromatic compounds which develop color by theaction of oxidizing agents after the amino compound is applied to thehair. The use of the oxidation dyes has generally required preliminarytests to determine the effect of the compound on the hair of theindividual since the reaction on the hair of all persons is not the sametoward these compounds. Another disadvantage of the oxidation dyesarises from the fact that considerable time, say a day or so, isrequired after the dyeing has been made to determine whether theultimate shade or effect of the compound on the hair will besatisfactory or similar to the approximation indicated by thepreliminary test. Probably the most serious objection to the use of theoxidation hair dyes is that these compounds are toxic to living personsand that even the least toxic among them is generally harmful to someindividual. More'recently a composition for hair dyeing was disclosedwhich comprises the non-poisonous water soluble coal tar dyes with urea,urethane or amides, such as formamide. Still more recently, there wasdescribed the process for the dyeing of hair which comprisespre-treating the hair with a cationic active fatty acid-aminecondensation'product with subsequent application of an aqueous solutionof a dyestuff. None of these methods heretofore used has been found tobe entirely satisfactory. It is therefore desirable to provide new hairdyes and new methods for their application that will preserve thenatural appearance of hair and that wi11 produce a large variety ofshades by processes which can be operated easily and conveniently toproduce final results in a very short space of time. Such processes andcompositions are especially desirable for the dyein of hair on pelts andfor the dyeing of hair on living persons.

It is among the objects of the present invention to provide newcompositions and processes for dyeing hair. Another object is to provideprocesses which will produce colored hair having a natural appearanceand in a large variety of shades. Another object of the invention is toprovide such compositions and processes which will give final resultsrapidly and satisfactorily at relatively low temperatures. A furtherobject is to provide rapidly acting hair dyes with good fastnessproperties without deleteriously affecting the natural appearance of thehair. Another object is to provide processes for the coloration of hairwhich will have good fastness properties but which can be prepared forrecoloration by a simple process Another object of the invention is toprovide compositions and processes for the dyeing of furs which will notcause irritation of the skin of the wearers. Still other objects of theinvention will be apparent from the following description.

The objects of the invention are attained in general by applying to thehair, and mildly heated, a. lake-forming metal salt and a water solublesynthetic organic dye, both of which are in aqueous solution.

The invention will be more fully set forth in the following moredetailed description which includes examples that are given asillustrative embodiments of the invention and not as limitationsthereof. Parts are expressed in parts by weight unless otherwise noted.

Example 1 Old gray hair which had been bleached was treated with a 5%mordant solution of ferrous sulfate and an 0.5% solution of thefollowing dye mixture simultaneously for 1-0 minutes at F.

Parts Pontachrome Brown G (C. I. 238) 45.5 Pontachrome Yellow SW (C. I.and

Prototype 56) 9.0

Logwood crystals (C. I. 1246) 45.5

dye solutions as low as 0.1%.

sulfate and 2.0% of the following dye mixture simultaneously for minutesat 110 F.:

Parts Pontachrome Brown G (C. I. 238) 6'7 Logwood crystals (C. I. 1246)33 The hair came to a final shade in 10 minutes and after about minutesthe hair was washed and dried. The hair had a natural appearance in adark brown shade. It has good washing and other fastness propertiesdesired for colored human hair. Penetration of the color was rapid andcomplete.

In a similar manner good dyeings were obtained by carrying out theprocess on old gray hair and on medium brown hair which had not beenprebleached.

Similarly, lighter shades of browns, such as drabs, can be made by usingconcentrations of ferrous sulfate as low as 0.25% solution and dyesolutions as low as 0.25%.

The advantages of a simultaneous application of ferrous sulfate and dyesolution are that it is a single operation and is saving in time and isless troublesome to the person being operated on. It will be obviousthat the more quickly the hair is dyed and the less handling required,the better the condition of the dyed hair as well as the comfort of theperson attached thereto.

Dry mixtures of ferrous sulfate and the various dye complexes,Pontachrome Brown G, Pontachrome Yellow SW, and logwood crystals, wereprepared in various concentrations varying from 20% iron sulfate and 80%dye to 80% ferrous sulfate and 20% dye. These intimate mixtures werestored for four months and at the end of this period trials were made onhuman hair using 0.5 to 2.0% solutions. The dyeings were carried out for10 minutes at 110 F. The shades produced were similar to those obtainedwhere the iron and dye solutions were applied separately and wheretheiron and dye solutions were dissolved separately and appliedsimultaneously.

Example 3 Old gray hair which had been bleached was wet with a 5.0%solution of ferrous sulfate for 10 minutes at a temperature of 110 F.The hair was squeezed to remove the surplus iron solution. It was thentreated with a, 1.0% solution of the following dye mixture.

Parts Pontachrome Brown G (C. I. 238) 2'7 Pontachrome Yellow SW (C. I.195 and Prototype 56)--- Logwood crystals (C. I. 1246) 48 assay-1cperior in depth of color to that obtained with only the firstapplication of iron solution. In a similar manner good dyeings wereobtained on pre-bleached medium brown hair and it is possible to obtaingood blacks with concentrations as low as 0.5% solutions of ferroussulfate and 0.25% solutions of dye in the first two treatments and 0.25%solutions of ferrous sulfate in the third treatment.

Example 4 Medium brown hair which had been bleached was wet with a 1.0%solution of the following dye mixture for 10 minutes at 110 F. The hairwas squeezed free of surplus color and treated for 10 minutes at 110 F.with a 1.0% solution of ferrous sulfate. Pm

Pontachrome Brown G (C. I. 238) 45.5

Pontachrome Yellow SW (C. I. 195 and Prototype 56) 9.0

Logwood crystals (C. I. 1246) 45.5

The hair came to a final shade in 10 minutes and after about 20 minutesthe hair was washed and dried. The hair had a natural appearance in adark brown shade and had good washing and other fastness propertiesdesired for colored human hair. Penetration of the color was rapid andcomplete. Similar results were obtained by v carrying out the process onold gray hair which had not been pre-bleached. In a similar mannerlighter shades of browns, such as drabs, were obtained by usingconcentrations of dyestuif as low as 0.1% dye solution and 0.25%solution oi ferrous sulfate. The predyeing operation can also be carriedout by acidulating the dye solution with an organic acid, such as aceticacid or formic acid. This method of application is particularlyadvantageous to the dyeing of hair of widely different texture andcondition found together in that it covers the various hairs moreuniformly and evenly.

Example 5 Medium brown hair was treated with a 1% solution containingparts of ferrous sulfate and 10 parts of a sodium salt of a technicaldodecyl alcohol sulfate. The treatment was carried out at F. by the samemechanics as for soap shampooing. This preparation combines a cleansingand mordanting operation whereby the natural oils and greases areremoved from the hair which is a necessary pretreatment for all hairdyeing operations and at the same time the iron solution becomes fixedto act subsequently as a mordant for a later application of dy solution.

One of the advantages claimed for this treatment is that it eliminatesthe soap shampoo customarily used before hair dyeing and in some casesthe pre-bleaching operations which is usually carried out with hydrogenperoxide before the dyeing. Dry physical mixtures containing 90 partsferrou sulfate and 10 parts of a sodium salt of a technical dodecylalcohol sulfate were prepared and stored for 6 months at roomtemperatures. At the end of this period a solution was used as a mordantto replace the ferrous sulfate solution cited in the foregoing examples.Its behavior was in all respects similar inasmuch as it produced withthe foregoing dye solutions, hair having a natural appearance, goodluster, and good washing and other fastness properties desired forcolored human hair. Penetration of the color was rapid and complete andequal to that in the foregoing examples where iron sulfate assume onlywas used. Similar results were obtained by carrying out the same processon old gray hair and medium brown hair.

Example 6 Old gray hair was treated for 10 minutes at 110 F. with a 2.0%solution of a. carbon type of betaine having an alkyl chain of 8-20carbon atoms at a pH of 8 or over. The hair was then dyed as in thevarious foregoing examples and it was found that this pro-treatmentincreased the amnity of mordant and dye solution for the hair. This isparticularly advantageous for the dyeing of old gray hair which is morediflicult to dye than young, healthy hair. Similarly, improved resultswere obtained by treatment with an 0.5% solution of a carbon type ofbetaine.

, Example 7 Dyeings were made by all of the methods illustrated inExamples 1 to 6. These dyeings were then subjected to a normal bleachingwith hydrogen peroxide such as is commonly used by hair dyeingoperations previous to dyeing. Solutions of hydrogen peroxide varyingfrom volume to 20 volume, made slightly alkaline with ammonia, were usedfor the treatments at a temperature of 110 F. and for a period of 20minutes. The colors were more or less completely removed from the hair.This property of these synthetic organic dyes being more or lesscompletely removed by bleaching is of great value to the operatorinasmuch as it allows the redyeing of hair from one color to another,without the necessity of, as at present. waiting for the hair to growout again before redyeing. It is also possible, because of thisproperty, to correct mistakes in dyeing which otherwise cannot becorrected satisfactorily for a long period.

Example 8 Medium brown hair was bleached by the application of a 20volume solution of hydrogen peroxide made slightl alkaline with'aquaammonia for 30 minutes at 110 F. This was applied with a brushresembling a tooth brush. Then in order to insure complete removal ofthe last traces of peroxide, the hair was dried. A /z% solution offerrous sulphate containing parts Der hundred of a sodium salt of atechnical dodecyl alcohol sulphate was then applied to the hair at 110F. by means of a shampooing operation similar to that for soapshampooing. This treatment wa carried on for 20 minutes. The surplusiron solution was then removed by squeezing. A solution of the followingdye solution was then applied with a brush for 2 hour at 110 F.

The hair was then shampooed to remove unfixed color and then dried. Thehair had a natural appearance in a dark auburn shade, having goodluster, good washing and other properties desired for human hair.

Example 9 One part of alum tanned rabbit pelt was treated by immersingin two parts of a 5% solution of a mixture containing 90 parts offerrous sulphate and 10 parts of a sodium salt of a technical dodecylalcohol sulfate for about 30 minutes at 110 F. The pelt was squeezed toremove the surplus solution. It was then treated with a 5% solution ofthe following dye mixture:

This treatment was carried out for 30 minutes at 110 F., after which thesurplus dye solution was removed by washing with water. The brown shadeproduced by this treatment was much deeper and much more level than onewhich could be produced by a like dye solution or unmordanted tannedrabbit pelt, which is known to be diflicult to dye at 110 F. The shadewas unusually fast to washing and crocking.

Example 10 One part of chrome tanned shearling (woolled heepskin) wastreated by immersing in two parts of a 5% solution of ferrous sulphatefor about 30 minutes at 110 F. The mordanted shearling was squeezed toremove the surplus solution. It was then treated with a 5% solution ofthe following dye mixture:

Parts Pontachrome Brown G 94 Logwood crystals 6 This treatment wascarried out for 30 minutes at F., after which the surplus dye solutionwas removed by washing with water. The tan shade produced by thistreatment was deeper and more level than one which could be produced bya like dye solution on unmordanted tanned shea'rlin g,

which is known to be difiicult to dye at 110 F.

Solutions of various water soluble lake-forming metal salts such asthoseof copper, aluminum, chromium and iron have been found particularlyvaluable for the processes of this invention. The iron salts, such asthe chlorides, sulfates and acetates and those of water soluble sulfatesof ferrous iron such as ferrous sulfate and ferrous ammonium sulfate arepreferred. The iron salts work more rapidly at a moderate lowtemperature than the chromium salts, they produce shades which are morelike the natural shades of human hair than the copper salts and theyproduce somewhat faster dyes, as a general rule, than the aluminumsalts. Ordinarily solutions are used which contain from about 0.25% toabout 5% of the metallic salt.

A solution of any of the various water soluble synthetic organic dyesselected from the class of chrome, acid, direct, disazo or basic dyescan be used. These dyes operate rapidly and produce a great variety offast shades which can be varied in a number of ways, as by using amixture of the dyes. For dyeing human hair the dyes classifled as watersoluble chrome dyes are preferred and among such dyes are the ones whichare devoid of the amine group.

The term chrome dyes refers to the synthetic organic dyes which aregenerally applied on animal fibers with sodium or potassium bichromateor a neutral chromate by any one of the three methods, i. e., bypremordanting with chrome salt, by after chroming with a chrome salt orby dyeing with dye and a chrome salt simultaneously and in the samebath. The term acid dyes refers to the synthetic organic dyes which areapplied on animal fibers in a neutral or acid bath. The term direct dyesrefers to the synthetic organic dyes which are generally applied onvegetable or cellulosic fibers and which vary in their animal fiberdyeing properties. The term diazo dyes refers to those synthetic organicdyes which are generally applied on vegetable or cellulosic fibers andwhich vary in their animal fiber dyeing properties. They can be dyeddirectly on vegetable fibers and then diazotizecl on the fiber andcoupled ,with such components as beta naphthol, phenyl methylpyrazolone, the arylides of beta hydroxy naphthoic acid, betametatoluylene diamine or other coupling components of similarproperties. The term basic dyes refers to those synthetic organic dyeswhich can be applied on animal fibers in a neutral or acid bath or onvegetable fibers premordanted with a metallic salt or a tannin-bearingorganic compound. Ordinarily the synthetic organic dyes of the classdescribed above are applied to cellulosic or animal fibers in dye bathswhich are heated to temperatures approaching that of the boiling pointof water, temperatures which cannot be tolerated by a human being or bypelts which have not been tanned by processes yielding thermally stableleather.

The dyes must be capable of being applied in the form of solutions andthe term water soluble dyes in the specification and claims refers todyes which are readily soluble in water as well as those which can bemore conveniently and rapidly put into solution by first dissolving in awater miscible organic solvent, such as alcohol and then diluting withwater to the desired strength for use.

As other illustrations of the many synthetic dyes which produce thedesired results which can be used alone or in mixtures of dyes similarto those specifically recited in the examples, the following arementioned as listed by Colour Index,

edited by F. M, Rowe and published by the Society of Dyers andColourists (England), namely, Colour Index Numbers 10, 21, 101, 109,151, 179, 203, 216, 234, 235, 246, 332, 420, 430, 561, 620, 640,652,655, 662, 696, 720, 749, 788, 789, 802,

Others to which Colour Index quinone, 1-amino-4-hydroxy anthraquinone,di-

ortho toluyl guam'dine salt of C. I. 208 (U. S. P. 1,674,128) di-orthotoluyl guanidine salt of amino G resorcin amino G acid (U. S. P.1,674,128)

and 4-nitro-2-amino-phenolmixture of 4 parts of metaphenylene diamineand 1 part metatoluene diamine Laurents acid.

The dye solution is ordinarily neither strongly alkaline nor stronglyacid inasmuch as in general the solubility of the dyes is decreased asthe acidity of the solution is increased and the aflinity of the dyes isdecreased as the alkalinity is increased. Ordinarily dye solutions willbe suitable for use if their pH is within the range of about 5 to about9.

. The solution of the lake-forming metal salt and the dye solution maybe applied at a temperature not less than 40 F. but the preferredtemperature for dyeing human hair is about 70 F. to about F., since theaction of the dye is faster, better quality dyeings are produced atthese temperatures and temperatures as high as about 110 F. are notunduly uncomfortable to the scalp. However, any higher temperature, sayabout F., can be used provided it does not injure the hair, the scalp orthe pelt. The term, mildly heated as used in this specification andclaims refers to temperatures of about 40 F. to about 130 F; Thesolutions, which are to be used, are heated and applied to the hair bythe means of cotton, 9. suitable brush or any other applicator in amanner somewhat similar to brush dyeing.

Reasons for the surprising effectiveness of the described processes forthe dyeing of hair are not fully understood, particularly because hightemperatures are required in the application of direct colors tocellulosic fiber and high temperatures and acid dye baths are usuallyused in the application of acid colors to animal fibers such as wool,Under the conditions by which acid colors are applied to wool in theabsence of acid, high temperatures appear to be necessary for the properfixation of the dyestufi. The results produced by the process of theinvention appear to indicate an unexpected afiinity of the hair for theheavy metal salts of the synthetic organic dyestuff. This peculiaraffinity of the hair for the heavy metal salt appears to-existindependent of whether the salt is formed prior to this application tothe hair as in Example 2 or whether it is formed in the hair asillustrated in Examples 1, 3, 4, 5, 6, 7 and 8.

This application is a continuation-impart of our application Serial No.324,084, filed March 15, 1940.

From the foregoing disclosure it will be recognized that the inventionis susceptible of modification without departing from the spirit andscope thereof and it is to be understood that the invention is notrestricted to the specific illustrations thereof herein set forth.

We claim:

1. The process of dyeing hair which comprises applying to the hair alake-forming metal salt and a water-soluble synthetic organic dye, saidsalt and dye being in aqueous solution and being heated to a temperatureof about 70 F. to about 110 F.

2. The process inaccordance with claim 1 in which the dye is a chromedye.

3. The process in accordance with claim 1 in which the lake-formingmetal salt is a ferrous sulfate.

4. The process in accordance with claim 1 in which an aqueous solutionof the lake-forming metal salt is applied to the hair and then anaqueous solution of the water-soluble synthetic organic dye is appliedwhile the hair is still moist,

said solutions being applied at a temperature of about 70 F. to about110 F.

' 5. The process inaccordance with claim 1 in which the aqueous solutionof the lake-forming metal salt and the aqueous solution of thewatersoluble synthetic organic dye are mixed before they are applied tothe hair.

6. The process in accordance with claim 1 in which the solution ofwater-soluble synthetic organic dye is applied to the hair before thesolution of the lake-forming metal salt is applied.

WILLARD FREDERICK VAN RIPER. WARREN JOHN ZINCK.

CERTIFICATE OF CORRECTION. Patent- No 2,558JU-6. Jenn-cry 11, 191411..

' WILLARD FREDERICK. VAN RIPER, ET AL. V

It is hereby certified that error appears in the printed specificationof the above numbered patent requiring correction as follows: Page 3,sec 0nd column, line 17, Exempl'e 9, for solut io n or read "solutionon-- and that the said Letters Patent hould be read with this correctiontherein that the same may conform to the record of the'case in thePatent Offic e. V

Sigmd andcsealed this 11pm day of march, A.- D. 191m.

, 7 Leslie Frazer Aet' ingjaommissioner of Patents.

